The present invention relates, in general, to flame-monitoring equipment, and, in particular, to a new and useful flame quality analyzer which utilizes a fiber optic array extending across a flame to be monitored, in conjunction with a a monochromator and detector array to produce signals which can be processed to display characteristics of the flame.
The operator of a multiburner furnace gets very little information concerning the status of the combustion inside the furnace. Each burner is usually provided with a flame detector to tell whether or not the flame is burning. Even this rudimentary information is difficult and expensive to get in many cases. Individual burners are also provided with a visual observation part. These, however, are severely limited in field-of-view and require the presence of an observer at the burner. Perhaps the best information is available through side doors which provide a wide-angle view of the burners adjacent the walls. Again, an observer is required at the door so routine use of the doors is limited. However, this is the primary source of information used by the startup engineer to set the burner for "optimum combustion". An obvious limitation is that only the burners near the wall are subject to observation.
Feeling the need for more information from the furnace interior, many furnace operators have installed TV cameras that view the flames from above. During startup and at low loads these systems are helpful, although plagued with maintenance problems. However, at normal loads the space between the cameras and the burners is usually filled with hot radiating particles that prevent any meaningful imaging.
There is a need for a device that tells the operator how well each of the individual burners in the furnace is performing. Such a device, in addition to providing a reliable flame on/off indication, would allow the operator to achieve higher system efficiency by identifying and adjusting poorly performing burners.
Previous attempts to meet this need have not been successful. Land Instruments in England and Environmental Data Corporation in the U.S. have offered devices for the purpose of burner performance monitoring and control. These devices provide an analog output which is used to "optimize" the combustion. Unfortunately, the output of these oversimplified devices does not correlate well with other measurements of flame quality under many conditions.